Billions of fluorescent tubes in ballasting fixtures are installed around the world. With the emergence of LED (Light Emitting Diode) technology fluorescent tubes are quickly becoming antiquated. A major technological advance was made to replace these fluorescent tubes when it was discovered an LED tube could emulate a fluorescent tube and be powered by the pre-existing ballast. The “ballast compatible” LED tube saves time, money and power for the end-user by still using previously installed fixtures and ballasts.
Replacing fluorescent tubes with ballast compatible LED tubes poses some new issues given their long lifetime of potentially 20-years or more. In some use environments, such as subways or industrial environments, these light tubes are subjected to extreme humidity and contaminating environments. These environments may not have been a problem with fluorescent tubes, because they needed to be replaced usually each year. However, now with the LED light tube in place for potentially 20-years or longer within these environments, contaminates and moisture can degrade internal components if the tube is not sealed properly. Also, years of contaminate buildup may deposit on the outside of the tube degrading light output and require periodic washing. Having a hermetically sealed LED light tube would be of benefit since washing a non-hermetically sealed tube may destroy it.
Many current replacement LED tubes have end caps that are typically larger in diameter than the tube. These end caps are also fastened by screws and clips. Therefore, these tubes do not ideally fit the form factor of the fluorescent tube, nor do they provide an adequate seal from the environment for their long usage lifetime. Improving the form factor and seal would be of benefit.
Lighting uniformity is an issue with LED light tubes. Fluorescent tubes by nature tend to provide uniform output as the excited gas atoms naturally distribute light evenly in all directions. However, LED light tubes consist of a limited number of discrete light emitting elements with limited angles of light emission. Replicating or even improving upon the uniform lighting of fluorescent tubes would further benefit the acceptance of LED tubes as replacements for fluorescent tubes.
Ballast compatibility is also an issue in some replacement situations. The new LED replacement tube needs to accommodate to the type of ballast present and produce optimum light output for that ballast.
The present invention aims to provide an LED light tube that improves upon the currently unresolved issues described above.